Abstract

The effects of carbon concentration on the crystal structure, magnetic, and electrical/thermal transport properties of ZnCxFe3 (1.0 ≤ x ≤ 1.5) have been investigated systematically. Both the Curie temperature and the saturated magnetization decrease firstly and then reach saturation with increasing x. The investigations of heat capacity and resistivity indicate that ZnC1.2Fe3 displays a strongly correlated Fermi liquid behavior considering its Kadowaki-Woods ratio (∼0.64 a0). Around the ferromagnetic-paramagnetic phase transition (∼358 K), a reversible room-temperature magnetocaloric effect is observed. The relative cooling power (RCP) is ∼164 J/kg (∼385 J/kg) with the magnetic field change ΔH = 20 kOe (45 kOe). Considering the considerable large RCP, inexpensive and innoxious raw materials, ZnC1.2Fe3 is suggested to be a promising candidate for room-temperature magnetic refrigeration. Furthermore, the studies of thermal transport properties indicate that ZnC1.2Fe3 can also be a potential thermoelectric material with the dimensionless figure of merit (ZT = α2T/ρk) reaching its maximum of 0.0112 around 170 K.

Received 20 July 2011Accepted 12 September 2011Published online 24 October 2011

Acknowledgments:

This work was supported by the National Key Basic Research under Contract Nos. 2007CB925002, 2011CBA00111 and the National Natural Science Foundation of China under Contract Nos. 51001094, 10974205, 10804111, 51171177, 11174295 and Director’s Fund of Hefei Institutes of Physical Science, Chinese Academy of Sciences. In addition, we also acknowledge Chen Sun very much for her help in the improvement of the English description of the manuscript.